Galvanic exchange-induced growth of Au nanocrystals on CuS nanoplates for imaging guided photothermal ablation of tumors

The conventional methods for constructing CuS-Au heterostructures in aqueous solution require the assistance of reducing agents such as NaBH4. Herein, without the additional reducing agent, we found that CuS nanoplates can be used as efficient nanoplatform and reducing agent for constructing CuS-Au heterostructures through the galvanic exchange route. The CuS-Au heterostructures were prepared by facilely introducing CuS nanoplates into HAuCl4 solution with continuous stirring, and the size (10-45 nm) and the number (1-3) of Au nanocrystals on CuS nanoplate were controlled by adjusting the Au/Cu molar ratios and stirring time. The obtained CuS-Au heterostructures possessed strong localized plasmon resonances (LSPRs) absorption in the near infrared (NIR) region, endowing them with the rapid photothermal response and high photothermal conversion efficiency of 36.5%. Moreover, due to the high atomic number of Au element, CuS-Au heterostructures were capable of high X-ray attenuation coefficient for X-ray computed tomography (CT) imaging. When CuS-Au dispersion was injected into the tumor of mice, the tumor could be monitored by CT and thermal imaging, and then thermally eradicated under the irradiation of 1064 nm laser. Therefore, the CuS-Au heterostructures were simply synthesized through the galvanic exchange route and served as efficient nanoagent for tumor theranostics.